Golang : Resize Image

Somehow...just feel like writing a tutorial on how to resize image with Golang today while writing out references for Golang's image package today.

Today's web application will most likely to include profile photo of the users and this usually involve cropping and resizing images uploaded by the users.

In this tutorial, I will use the resize photo functions from this excellent https://github.com/disintegration/imaging package - a fairly simple and compatible with standard Go's image packages.

With much further ado, here's the codes :

 package main

 import (
 "github.com/disintegration/imaging"
 "os"
 "runtime"
 "fmt"
 )

 func main() {

 // maximize CPU usage for maximum performance
 runtime.GOMAXPROCS(runtime.NumCPU())

 // load original image
 img, err := imaging.Open("./big.jpg")

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }


 // resize image from 1000 to 500 while preserving the aspect ration

 // Supported resize filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali,
 // CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine.

 dstimg := imaging.Resize(img, 500, 0, imaging.Box)

 // save resized image
 err = imaging.Save(dstimg, "./resized.jpg")

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 // everything ok
 fmt.Println("Image resized")

 }

Here are some of the resized image samples :

Big.jpg(original)

Gaussian

Lanczos

Box

Notes :

In case you have trouble getting the imaging package. See this how to set GOPATH and fix the cannot error tutorial.

References :

http://godoc.org/github.com/disintegration/imaging